Geocronologia del plutón de Campanario-La Haba (Badajoz) a partir del análisis de isótopos de Pb en circones y U-Th-Pbtota| en monacitas

Abstract

The Campanario-La Haba pluton is located to the north of the Los Pedroches batholith in the southern part of the Central-lberian Zone. The age of the emplacement had been established between 304 and 314 Ma using K-Ar and Rb-Sr methods. In this study we have applied two different new techniques in an attempt to precise the age of the intrusion. The results obtained, are as follows: (1) the Pb isotopic composition of five zircon fractions have yielded a 206Pbl204Pb vs. 207Pb/204Pb isochron of 307 ± 16 Ma (MSWD = 0,33); (2) the U-Th-Pb content of monazites analysed by EM PA does not allow for reliable age results; althouth their ages are close to those obtained by other methods, there is distinct evidence of Pb-loss processes subsequent to the crystallization of this mineral, for which reason the ages obtained must be handled with care. The age of the postcrystalization events and their significance remain unknwon